With the ever development of Thin Film Transistor Liquid Crystal Display (TFT-LCD) technologies, various novel semiconductor devices and application thereof to display devices also experienced rapid advance.
During the fabrication procedures of conventional TFT-LCDs, more and more manufacturers try to replace amorphous silicon (a-Si) TFTs or Low Temperature Polycrystalline Silicon (LTPS) TFTs with Oxide TFTs, such that display products of higher quality may be developed. Oxide TFT back plate technology is a back plate technology with a similar fabrication procedure to conventional a-Si TFTs. In the oxide TFT back plate technology, the original silicon semiconductor material applied to the a-Si TFT is replaced by an oxide semiconductor material, such as the currently most popular Indium Gallium Zinc Oxide (IGZO), to form a semiconductor active layer of the TFT. FIG. 1 schematically illustrates a typical conventional array substrate with oxide TFTs, which comprises a gate electrode of a TFT, a gate insulation layer 12 and a semiconductor active layer 13 sequentially formed on a transparent substrate 10, the semiconductor active layer 13 is formed from IGZO. An etch stop layer 14 with via holes A and B are formed on the semiconductor active layer 13 through a patterning process, the via holes A and B respectively penetrate through the etch stop layer 14 to expose the semiconductor active layer 13. A source electrode 151 and a drain electrode 152 of the TFT are connected to the semiconductor active layer 13 respectively through the via holes A and B.